Oven-thermometer.



No. 887,447. PATENTED MAY 12, 1908.

4 A. E. WHITTIER.

OVEN THERMOMETER.

APPLICATION TILED JAN.22. 1908.

I y 3 4 /4 /Z /4 UNITED STATES PATENT OFFICE.

ALBERT E. WHITTIER, OF BRISTOL, CONNECTICUT, ASSIGNOR TO THE CONNECTICUT TRUST & SAFE DEPOSIT COMPANY, OF HARTFORD, CONNECTICUT, A CORPORATION OF CON- NECTICUT.

OVE N-THE RMOME TER Specification of Letters Patent.

Patented May 12, 1908.

T 0 all whom it "may concern:

Be it known that I, ALBERT E. WIIITTIER, a citizen of the United States, residing at Bristol, in the county of Hartford and State of Connecticut, have invented a new and use ful Oven-Thermometer, of which the follow ing is a specification.

This invention relates to those devices which are designed to be attached to the walls of ovens of wood, coal, gas, oil and electric stoves and ranges, for the purpose of indicating the temperature of such ovens in order that baking, roasting and the like cooking may be accomplished with certainty and exactness, and with a saving of time and fuel.

The object of this invention is to simplify the construction of one of these thermometers, and thereby cheapen the cost and at the same time render it more sensitive and less liable to injury.

Figure 1 of the accompanying drawings shows a front view of an oven thermometer which embodies the invention. Fig. -2 shows a rear view of the same with the protecting cap removed. Fig. 3 shows a diametrical section on the plane indicated by the dotted line 33 on Fig. 2. Fig. 4 shows a section on the plane indicated by the dotted line l 1 on Fig. 2 and illustrating a modified construction.

The frame 1 of this device may be stamped to shape from sheet metal or may be cast to the desired form, and it is usually provided with wings 2, having perforations 3 by means of which it can be attached to the wall of the oven with which it is to be used. The frame is commonly fastened by stove bolts to the inside of the lining of the door of the oven.

Fastened on the back of the frame is a case 4, preferably stamped of sheet brass, and screwed to this case and projecting forwardly through the frame is a cylindrical case 5, in which is a dial 6, that desirably has temperature indications and also hour indications. Over the front case and protecting the dial is a glass 7 held in place by a flanged ring 8, which slips upon the front end of the cylinder.

In the case that is secured to the rear of the frame, with one end fastened to the edge of that case, is the curved thermostatic arm 9, which as usual is formed of strips of metal having different co-efficients of expansion. The free end of the thermostatic arm is connected by a link 10 with a portion of the segment 11 which is mounted on an arbor 12,

which has one end supported by the back of the case, and the other end supported by the bridge 13 which is mounted on posts 14. The curved edge of the segment is provided with gear teeth which are arranged to mesh With the teeth of the pinion 15 on the arbor 16, which is supported by the bridge and by the wall of the case, and that extends forwardly through the frame into the front cylinder, where in front of the dial it carries an indicating pointer 17.

The bridge 13 is formed with rearwardly projecting feet 18 which extend outwardly to the plane of the back edge of the rim of the rear case. Over the back of the rear case and fitting the rim is a cap 19. It is, of course, desirable to make the rear case and its cap of as thin metal as is consistent with strength, in order that the heat rays may act upon the thermostat with as little impedance as possible, so that the device will be sensitive and will change with each variation of temperature in the oven, rather than be logy and slow to change under slight variations of heat in the even as results from the retaining of heat when a heavy mass of metal surrounds the sensitive thermostatic arm. It is necessary however to have the case surrounding the thermostatic arm and the segment and pinion, rigid so that the parts will not become jammed and disarranged by accident, for instance as when a door carrying the device is pushed violently against a cooking utensil or a hard substance being baked or roasted in the oven.

By providing the bridge with feet that project rearwardly to the plane of the edge of the case, so that when the cap is put in place the feet will bear against it and support it, the cap can be made of very thin metal so that it will offer but little impedance to the heat rays and will not have sufficient bulk to hold the heat and prevent the thermostatic arm from indicating slight variations of temperature in the oven, for the feet on the rigid bridge will support this light cap in such manner that there is no danger of its being dented or jammed inwardly sufficiently to interfere with the free working of the sensitive thermostatic arm or the segment and retatory pinion on the arbor which carries the pointer. This also, besides increasing the efficiency of the device by rendering it more sensitive, cheapens it so that it can be furnished to the user at less cost If desired, as shown in Fig. 4, the posts 14 which support the bridge can be carried rearvwardly to the plane of the edge of the rim of the case so as to support the back of the cap and prevent it from being jammed inwardly.

The invention claimed is:

VAn oven thermometer having a frame, a case secured to the frame, a thermostatic arm arranged within the case, a toothed segment connected with the thermostatic arm, a pinion meshing with the toothed segment, a bridge supporting the arbors of the segment and pinion, feet extending rearwardly from the bridge, a cap protecting the thermostatic arm, segment and pinion, said cap fitting the edge of the case and being supported from collapse by the feet projecting from the bridge, a dial, and an indicating pointer on the pinion arbor in front of the dial, substantially as specified.

ALBERT E. WVHITTIER. Witnesses:

ALBERT E. GooDwIN, M. AGNES HODGDON. 

